Pension and Other Retiree Benefits (Pension Benefit Obligation and Funded Status) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Change in plan assets
Employer contributions		$ 20.9
Amounts recognized in the Consolidated Balance Sheets consist of:
Pension and post-retirement benefit obligations		257.2	$ 275.5
Pension | U.S.
Change in projected benefit obligation (PBO)
Projected benefit obligation at beginning of year		206.5	200.1
Service cost		1.6	1.4	$ 1.3
Interest cost		6.7	7.1	7.3
Actuarial (gain) loss		(15.6)	14.7
Participants’ contributions		0.0	0.0
Benefits paid		(10.9)	(16.8)
Curtailment gain		0.0	0.0
Settlement gain		0.0	0.0
Plan amendments		0.0	0.0
Foreign exchange rate changes		0.0	0.0
Esselte Acquisition		0.0	0.0
Other items		0.0	0.0
Projected benefit obligation at end of year		188.3	206.5	200.1
Change in plan assets
Fair value of plan assets at beginning of year		162.1	150.5
Actual return on plan assets		(15.8)	21.1
Employer contributions		5.7	7.3
Participants’ contributions		0.0	0.0
Benefits paid		(10.9)	(16.8)
Settlement gain		0.0	0.0
Foreign exchange rate changes		0.0	0.0
Esselte Acquisition		0.0	0.0
Other items		0.0	0.0
Fair value of plan assets at end of year		141.1	162.1	150.5
Funded status (Fair value of plan assets less PBO)		(47.2)	(44.4)
Amounts recognized in the Consolidated Balance Sheets consist of:
Other non-current assets		0.0	0.0
Other current liabilities		0.0	0.0
Pension and post-retirement benefit obligations	[1]	47.2	44.4
Components of accumulated other comprehensive income, net of tax:
Unrecognized actuarial loss (gain)		64.7	56.9
Unrecognized prior service cost (credit)		1.5	1.7
Pension | International
Change in projected benefit obligation (PBO)
Projected benefit obligation at beginning of year		695.0	345.1
Service cost		1.9	1.9	0.8
Interest cost		12.9	13.4	10.3
Actuarial (gain) loss		(26.6)	13.2
Participants’ contributions		0.1	0.1
Benefits paid		(26.9)	(26.5)
Curtailment gain		(0.9)	0.0
Settlement gain		(2.0)	0.0
Plan amendments		6.8	0.0
Foreign exchange rate changes		(35.3)	59.8
Esselte Acquisition		0.0	288.0
Other items		2.3	0.0
Projected benefit obligation at end of year		627.3	695.0	345.1
Change in plan assets
Fair value of plan assets at beginning of year		463.8	302.7
Actual return on plan assets		(10.0)	21.3
Employer contributions		14.9	14.0
Participants’ contributions		0.1	0.1
Benefits paid		(26.9)	(26.5)
Settlement gain		(2.0)	0.0
Foreign exchange rate changes		(24.6)	38.2
Esselte Acquisition		0.0	114.0
Other items		2.3	0.0
Fair value of plan assets at end of year		417.6	463.8	302.7
Funded status (Fair value of plan assets less PBO)		(209.7)	(231.2)
Amounts recognized in the Consolidated Balance Sheets consist of:
Other non-current assets		1.4	0.6
Other current liabilities		6.7	6.9
Pension and post-retirement benefit obligations	[1]	204.4	224.9
Components of accumulated other comprehensive income, net of tax:
Unrecognized actuarial loss (gain)		97.1	100.5
Unrecognized prior service cost (credit)		5.0	(0.2)
Post-retirement
Change in projected benefit obligation (PBO)
Projected benefit obligation at beginning of year		6.8	6.7
Service cost		0.1	0.0	0.1
Interest cost		0.2	0.2	0.2
Actuarial (gain) loss		(0.3)	0.0
Participants’ contributions		0.1	0.1
Benefits paid		(0.4)	(0.5)
Curtailment gain		0.0	0.0
Settlement gain		0.0	0.0
Plan amendments		0.0	0.0
Foreign exchange rate changes		(0.3)	0.3
Esselte Acquisition		0.0	0.0
Other items		0.0	0.0
Projected benefit obligation at end of year		6.2	6.8	6.7
Change in plan assets
Fair value of plan assets at beginning of year		0.0	0.0
Actual return on plan assets		0.0	0.0
Employer contributions		0.3	0.4
Participants’ contributions		0.1	0.1
Benefits paid		(0.4)	(0.5)
Settlement gain		0.0	0.0
Foreign exchange rate changes		0.0	0.0
Esselte Acquisition		0.0	0.0
Other items		0.0	0.0
Fair value of plan assets at end of year		0.0	0.0	$ 0.0
Funded status (Fair value of plan assets less PBO)		(6.2)	(6.8)
Amounts recognized in the Consolidated Balance Sheets consist of:
Other non-current assets		0.0	0.0
Other current liabilities		0.6	0.6
Pension and post-retirement benefit obligations	[1]	5.6	6.2
Components of accumulated other comprehensive income, net of tax:
Unrecognized actuarial loss (gain)		(3.5)	(3.6)
Unrecognized prior service cost (credit)		$ (0.2)	$ (0.2)

[1] Pension and post-retirement benefit obligations of $257.2 million as of December 31, 2018, decreased from $275.5 million as of December 31, 2017, primarily due to cash contributions and favorable foreign currency translation.